Electric defroster for refrigerating coils



"bee. 31, 1929. 1,742,062

W. B. DAY

ELECTRIC DEFROSTER FOR REFRIGERATING COILS Filed Dec. 15 192'.

Dec. 31, 1929.

W. B. DAY

ELECTRIC DEFROS'IER FOR REF RIGERATING COILS Filed Dec. 15 1927 INVENTOR E e BY ATTORNEY Patented Dec. '31, 1929 UNITED STATES PATENT OFFICE ILLIAM 3'. DAY, or LEXINGTON, KENTUCKY, assxenon or one-HALF 'ro nrnam w. anmcx, or WINCHESTER, KENTUCKY l 1 anaemic :onrnosrnn ron mnrenmrme coins Application filed ecember 15, 1927. Serial No. 240,256.

This invention relates to defrosting apparatus for refrigerating machines and more particularly to electrical means for this purose. p A primary object of this invention is to provide means for automatically applying electric heat at redetermined intervals to the cooling units 0 a refrigerating plant whereby the accumulation of any appreciable amount of frost on said units will be prevented.

Another object is to provide an intermittently operated device actuated by the refrigerating compressor for controlling the application of heat to the cooling units, and thereby ensure the automatic defrosting of said units.

In carrying'out these objects, the invention is susceptible of a wide range of modification without departing from the spirit or sacrificingany of the advantages of the claimed invention; there beingshown in the drawings for illustrative purposes a preferred and 'prac tical form, in whic Figure 1 represents a perspective of the electric heater control constituting a part of this invention, parts being broken out and in section; and

Fig. 2 is a side elevation thereof.

In the embodiment illustrated the control device constituting a part of this invention comprises an electric circuit closer 1 the wires 2 and 3 from which lead to heating coils 30, which are connected in seriesand-arranged in contact with the cooling units 35 of a refrigerating plant, and which, when in operation melt ofl the frost and ice from the units. The

contact 4 of this circuit closer is fixed while the contact 5 which cooperates therewith is movable and is carried by a spring, arm 6 mounted on a 1ever.7 fulcrumed at one end to a laterally extending bracket 8 carried by a suitable supporting structure.- At the free end of the lever 7 is a roller 9 which is arran ed in the path of the periphery of a rotata I mounted wheel 10 having a radially exten ing cam 11 on the periphe thereof which is designed to enga e the rol er 9 during the rotation of the w eel and force the lever 7 toward contact-4: thereby causing the contact 5 carried by said lever to en age the contact 4 and close the electric circu t, send ing current through the wires 2 and 3 to the heatingcoils above described.

The wheel 10 has an annular series of ratchet teeth 12 on one face thereof and is rotatahly mounted on a suitable shaft 13. A

pawl 14 is positioned to engage the teethand is carried at one end of an arm 15 pivotally mounted at 17 on a su porting structure 18. This arm 15 has depen ing therefrom a pointed prong 16 which is arranged in contact with sylphon bellows 19 which is controlled by a vacuum from the refrigeratin compressor (not shown) with the pipe 2% leading to said compressor. This device is designed to be used in connection with what is known as the flooded system which has a boiler in the refrigerator and is part of and also to pull down the lever 15 to the point where the pin 14 will engage behinduanother notch 12 of the wheel 10. The number of teeth 12 on the gear wheel 10 determine how long will be required before the circuit closes on the heated coils. When the lever is down it will so remain until the bellows again expand which in turn causes the lever 15 to o erate to turn the gear wheel another toot No defrosting, however, takes place until the wheel 10 makes one complete revolution, be-

ing slowly turned by the actuation of one notch at a time. the wheel 10 has 24 teeth it will defrost once intwenty-four hours for a few minutes and then move away from the contact which closes the circuit for operating the electric heatin coils. It will be understood that as the be lows .19 expands and contracts the lever 15 will be actuated and thereby rotate the wheel revent the I It will thus be seen that if 10 by engagement of the pawl 14 with the teeth 12 of said wheel. It will thus be seen that the rotation of the wheel 10 of course causes the cam 11 to revolve and when said 3am contacts the roller 9 it forces the lever 7 on which the roller is mounted away from the wheel, thereby causing the contact 5 of the circuit closer to engage the contact 4 and close the circuit and supply suflicient heat to the coils to cause them to melt off the frost on the cooling units 35.

A coiled spring 21 is arranged between the lever 7 and an adjusting screw 22 mounted in the support S and is designed for controlling the engagement of the roller 9 with the periphery of the wheel 10, the wheel being made easier or harder to turn by adjusting the screw 22 for varying the tension of the spring 21 which opposes the bellows 19 to any desired de ree.

rom the above, it will be obvious that this controlling device is automatic and through the circuit closer I the heat will be applied intermittently to the cooling units for a short period of time, sufiicient to melt the ice and frost which may accumulate thereon, in so many running hours of the machine.

From the above description, it will be obvious that after this deviceis once connected up with the refrigerating machine, no further attention is necessary, and it will automatically apply and cut-off heat at predetermined intervals controlled by the number of teeth 12 on the ratchet wheel. a 7

Without further description it is thought that the features and advantages of the invention will be readily apparent to those skilled in the art, and it will of course be understood that changes in the form, proportion and minor details of construction may be resorted to, without departing from the spirit of the invention or its scope as claimed.

I claim 1. The combination with a refrigerating coil; of an electric heating coil arranged in close proximity thereto, and automatically operated means for energizing said heating coil at intervals whereby the refrigerating coil is freed from snow and ice.

2. The combination with a refrigerating coil; of an electric heating coil arranged adjacent thereto, and automatically operated means for energizing said heating coil at predetermined intervals whereby the refrigerating coil is freed from ice and snow.

3. The combination with a refrigerating machine including a coil and a compressor; of an electric heating coil arranged adjacent said refrigerating coil, an electric circuit controlling said heating coil, and automatically 0 erated means for opening and closing said circuit whereby the electric coil is energized at intervals and the ice and snow formed on the refrigerating coil melted thereby.

4. The combination of a sylphon bellows adapted to be actuated by a refrigerating compressor, normally open electric contacts, and means operated intermittently by said bellows for closing said contacts.

5. Means forv closing an electric circuit comprising normally open electric contacts, alever on which one of said contacts is mounted, a roller carried by said lever, a cam wheel mounted to engage said roller to operate said movable contact into engagement with the fixed contact at predetermined intervals, a pawl and ratchet mechanism for operating said wheel, and suitably operated bellows for actuating said ratchet mechanism.

6. The combination of a sylphon bellows adapted to be actuated by pressure in the suction side of a refrigerating clamp, a pawl carrying lever having engagement with said bellows and adapted to be operated thereby, a ratchet wheel having teeth located in the path of said pawl whereby the wheel is operated, a cam carried by the periphery of said wheel, normally open electric contacts, a lever on which one of said contacts is mounted and having a roller positioned for engagement by said wheel cam for intermittently closing the contacts when said roller is so engaged.

7. The combination of a sylphon bellows adapted to be actuated by pressure in the suction side of a refrigerating clamp, a pawl carrying lever having engagement with said bellows and adapted to be operated thereby, a ratchet wheel having teeth located in the path of said pawl whereby the wheel is aperated, a cam carried by the periphery of said wheel, normally open electric contacts, a lever on which one of said contacts is mounted and having a roller positioned for engagement by said wheel cam for intermittently closing the contacts when said roller is so engaged, and means for controlling the tension of the lever to vary the frictional engagement of the roller with the wheel.

Signed at Lexington in the county of Fayette and State of Kentucky this twelfth day of December A. D. one thousand nine hundred and twenty-seven.

WILLIAM B. DAY. 

